EP0909996A2 - Clock/radio powered by solar energy - Google Patents

Abstract

The solar-powered radio clock (11) has a power store (210 for operating inter alia an electromechanical transducer (15) for the time display (12). A step monitor (25) triggers an at least partial restart of the radio clock in the event of a shortened or interrupted drive pulse caused by an inadequate state of charge of the power store.

Description

The invention relates to a solar powered radio clock according to the preamble of Claim 1.

Such a radio clock is known from EP-A-0 208 986. In there is the query of energy storage for the photovoltaically generated electrical charges described two different levels to increase with increasing storage voltage Start of operation initially only the consumers necessary for the start in To put operation. The other consumers are only switched on when the storage has reached a higher energy level due to further recharging. This ensures that not at the beginning of the voltage increase on Memory an overload occurs with the result of the voltage collapse, because otherwise the just starting operation without reaching a steady operating state would be switched off again immediately. To those at the start of operations necessary functions for finally reaching a steady operating state the clock includes the work of the processor and the receiver a radio clock of the type described in more detail, for example, in EP-B 0 180 880 is. The pointer position detection of the radio clock leads to the automatic correction of the Pointer position as soon as valid current time information is received by radio and could be decoded in the processor. So the consumer needs for that Do no handling at the start of operation: As soon as enough light energy the clock sets to ensure that the memory is sufficiently charged operates automatically and finally automatically sets itself to the correct one Time display on.

It is problematic, however, that towards the end of the operation an inconspicuous and then slowly increasing pointer error indication can occur. It is not acceptable for a radio controlled watch advertised as the most accurate of all conceivable consumer watches will and because of this exactness - as well as due to the lack of operating requirements - great acceptance on the market. The present invention is therefore based on the task of avoiding such false reports that occur if, at the end of the operation, the energy still contained in the storage is for the separately buffered operation of a processor for electro-optical display control is still sufficient, but not for the reliable operation of the electromechanical Transducer for a timed pointer movement. The latter is namely no longer guaranteed if the Drive impulse for the motor movement starts, but then not over its full predetermined length is due, but due to the electrical load of the almost empty memory for the temporary collapse of the Residual voltage leads. The result is that none of the problems that occur as a result two shorter partial pulses for the operation of the engine provides sufficient energy. The remaining, in particular electro-optical, Functions such as the continuous digital display of seconds on a display but are ultimately continued undisturbed, so that the actual pointer position increasingly compared to otherwise displayed time-derived Information, and of course also in relation to the actual passage of time remains. The rapid traction drive phase is no less critical, in order to swivel the hands quickly into a certain angular position (cf. EP-B 0 180 155), especially in the course of at the start of operations and then from time to time for any necessary pointer position correction automatically triggered pointer position control based on the time determined by radio. Because during the proofreading occurring high walking speed with a correspondingly increased dynamic Load of the stepper motor due to the moment of inertia of the clockwork gear represents an extreme load on the energy source and the drive system, which is why the risk of losing a motor step is particularly high. If not a motor step is actually carried out with every step pulse is - and also with interrupted motor impulses -, the result of the Motor drive pulse count no longer with the actually executed one Number of steps matched, so that the pointers no longer correspond to those required by the Step number given the angular position rotated and consequently incorrectly displayed.

The object of remedying this is achieved according to the invention in that an operating circuit with a so-called step monitor is provided, the triggers at least a partial restart and preferably a processor reset if a drive pulse occurs that no longer has the necessary energy content for the Includes step control of the electromechanical transducer.

The function of this step monitor provided here according to the invention corresponds So not that of a control and control circuit that minimizes the Power consumption of a clock stepper motor is known and is based on the step pulse to control the electromotive converter successively shorten - until it is no longer sufficient for step operation and therefore after Inserting a high-energy correction pulse is extended again, the According to the state of the art, whether an motor step was carried out correctly Technology usually detected inductively by means of an electrodynamic circuit becomes.

The step monitor used according to the invention, on the other hand, prevents a false display, by switching off at least essential parts of a radio clock and new be started. In particular, the recipient also wins of a current time telegram is switched on in order to then move the pointer to the one that is now applicable Rotate angular position - when the stored operating voltage is up to has not finally dropped so far that no new commissioning at all the radio clock can do more (before the memory from its photovoltaic Reload the cell to above the critical operating voltage threshold is).

Fig. 1

im Blockschaltbild eine solarbetriebene Funkuhr mit Realisierung der erfindungsgemäßen Betriebsabschaltung und

Fig. 2

(2a bis 2d) das Verhalten der Betriebsabschaltung in Abhängigkeit von der Impulsform der Motoransteuerung.

Additional alternatives and further developments as well as further features and advantages of the invention result from the further claims and from the following description of a preferred implementation example for the solution according to the invention, which is sketched in a highly abstracted manner and limited to the essentials. The drawing shows:

Fig. 1

in the block diagram a solar-powered radio clock with implementation of the operational shutdown and

Fig. 2

(2a to 2d) the behavior of the shutdown depending on the pulse shape of the motor control.

The solar-powered radio-controlled clock 11, which is simplified in terms of the block circuit diagram in FIG. 1 The genus defined in more detail at the beginning has an electromechanical time display 12 approximately in the form of numerical flaps or preferably equipped with pointers 13. The pointers 13 are kept out of time by a processor 14 or a separate, preferably quartz-stabilized, clock circuit via at least one electromechanical converter 15, in particular a stepper motor, and the gear system the pointer mechanism 16 moves. The control of the converter 15 with drive pulses 17 (FIG. 2a) usually takes place via an approximately active one Bridge network designed driver circuit 18th

For the monitoring already mentioned at the beginning and, if necessary, for correction the time display 12 is from the processor 14 at the start of operation and then by time currently a receiver 19 temporarily turned on, which is a coded absolute Receives time information and as a demodulated telegram 20 for decoding delivers to processor 14. The one obtained in the processor 14 by decoding absolute time information is (also in processor 14) with the current one Position of the pointer 13 compared to if necessary - in addition to the time-keeping Periodicity of the regular drive pulses 17 - correction drive pulses to deliver to the converter 15. A pointer level control circuit, preferably on a light barrier query of certain wheel positions in the pointer mechanism 16 is based (cf. EP-A 0 529 390), the processor 14 leaves the respective one Detect passage of the pointer 13 through a reference position and then the continue to count driving impulses 17 until the pointers 13 are correct Angular position with respect to the absolute time transmitted by radio.

This radio-controlled operation of the clock 11 takes place from a chemical or physical Charge energy storage 21, which consists of a photovoltaic cell 22 (commonly referred to as a solar cell) is recharged. One also as a solar manager Operating control 23 to be designated ensures that the memory 21 on the one hand not overloaded from cell 22 and on the other hand not by consumers the radio clock 11 is discharged below an operationally critical voltage level. In This, connection, the operation control 23 can also perform the task via the processor 14 at the start of operation only the functionally essential consumers to switch to the memory 21, so that its not yet at full operating level increased voltage does not fall below the level due to high load Operating limit drops, as described in EP-B 0 208 986. Furthermore or in addition, the operating control 23 according to EP-B 0 285 838 can also be used for this ensure that depending on the operating conditions dispensable consumers for protection of the memory 21 can be temporarily switched off. This applies in particular the night time, if there is no reloading of the memory 21 in the dark from the cell 22, which is why functions can be switched off would only disturb at night anyway or would practically not come into its own - how about an hourly chime or the time display 12 which is not readable at night anyway Pointer 13 or in the display 24. When it comes next after exposure to light Tomorrow the charging situation of the memory 21 will be improved sufficiently has, the operational control 23, the sub-function lock is released again and in particular the receiver 19 turned on in the manner described above Way the position of the pointer 13 again in line with the current given time.

It has proven to be problematic, however, that when the state of charge has dropped sharply of the memory 21, that is to say shortly before the end of operation, incorrect positions of the pointers 13 can occur not immediately, but only when the pointer moves through the next time can be recognized and corrected by a reference position in the pointer mechanism 16. Such a, even if your fleeting viewer at first hardly noticeable, Neither is the image of the extreme precision of a consumer radio clock 11 but not acceptable.

It has been shown that such a failure occurs because the current Loading of the almost discharged memory 21 by a drive pulse 17 (Fig. 2a) temporarily and so briefly to the collapse of the storage voltage leads that the processor 14 equipped with a buffer 30 on the operational side continues uninterrupted, but while the drive pulse 17 to two consecutive Sub-pulses 17 'and 17' '(Fig. 2c) is interrupted. From none of which is energetically sufficient to support the converter 15 with its load to move the pointer mechanism 16 one step further. That means that Radio clock 11 compared to the progressing absolute time and compared to the Display 24 electro-optically displayed time information loses one step each time, that is, an increasing false report provides. That is unacceptable, especially since At first visually barely noticeable error indication with failure of further motor steps enlarged, although the radio clock 11 on the part of the processor 14 (but information not controlled via the converter 15) continues to work correctly.

According to the present invention, a step monitor is used to intercept this malfunction 25 provided, as outlined in Fig. 1 separately, but also in the frame the functionality of the processor 14 can be realized. This step monitor 25 is from the starting edge 26 of each step pulse 17, expediently delayed by a predetermined range v to generate a control window 27 of the gate length t (with v + t <T according to FIG. 2 a / b) initiated. It's over before the pulse duration T of the drive pulse 17 (typically 8 milliseconds, for example Length of common small watch stepper motors as the walking 15) expired is. If within the window 27, ie before the end of the gate length t (Fig. 2b), one End edge 28 occurs (Fig. 2c), then the drive pulse 17 does not have the energy content according to its continuous pulse duration T (Fig. 2a), but it is at least interrupted - namely as a result of a temporary breakdown of the operating voltage, that is, as a result of the current shortfall of what is necessary for operation Levels at memory 21. Therefore, neither the sum nor even each individual the chopped impulses 17 '+ 17' 'to a correct step movement of the Motor 15 lead. In this case, the step monitor 25 delivers a reset command 29 (FIG. 2d) to the processor 14. This leads to the initiation of a restart Correction of the time displays of the radio clock 11 as described above; which one but is actually only carried out if the power reserve of the Memory 21 is still sufficient for this. Otherwise, the radio clock 11 remains by the of the storage voltage-dependent operating control 23 is switched off until it is due to sufficient charge increase in memory 21 again initiated a restart.

This ensures that in the event of an incorrect time display 12 which is insufficient energy reserve for the operation of the converter 15 decreases, not a faulty one Operation begins, but the radio clock 11 for display synchronization restarted or completely switched off (when the memory 21 is unloaded).

In the case of a solar-powered watch, the operating voltage can therefore drop permanently below the switch-off level to a false indication because not more each pulse 17 for the electromechanical converter 15 to advance the display is sufficient, since the impulse loading leads to an at least short-term Collapse of the already critically lowered operating voltage leads the solar cell buffer memory 21. With a solar powered radio clock 11 therefore, according to the invention, carries out the interruption detected by a step monitor 25 or shortening a drive pulse 17 for the time-keeping pointer movement to trigger a reset command 29 to the receiver 19 of the Turn on radio clock 11 and thereby the radio clock processor control Pointer position automatically on the decoded from the current time telegram correct absolute time.

Claims (3)

Solar-powered radio clock (11) with energy storage (21) for, among other things, the operation of an electromechanical converter (15) for time display (12)
characterized by
that a step monitor (25) is provided, which triggers an at least partial restart of the radio clock (11) when the drive pulse (17) is shortened or interrupted due to the insufficient state of charge of the energy store (21). Radio clock according to claim 1,
characterized by
that the step monitor (25) delivers a reset command (29) to a processor (14) for the operation of the time display (12) and the radio-clock receiver (19) if - depending on the onset of a drive pulse (17) - started before the expiration of one - Control window (27) an end edge (23) of the drive pulse (17) occurs. Radio clock according to claim 1 or 2,
characterized by
that the step monitor (25) starts a delayed gate length (t) by a predetermined time span (v) compared to the starting edge (26) of a drive pulse (17), the sum of the delay span (v) and gate length (t) is less than the regular pulse duration (T) of the drive pulse (17).

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